This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Introduction. Nonhuman primates used in biomedical research can be provided the best quality of life if their management takes their disease status into consideration. For example, it is important to understand how to best meet the social needs of primates throughout the progression of the Simian Immunodeficiency Virus disease. This study aims to 1) characterize the changes in psychological wellbeing associated with Simian Immunodeficiency Virus disease progression, 2) determine the correspondence between measures of wellbeing and disease-related changes in physiology, and 3) identify any threshold behavioral or physiological values that should be used to trigger either increased scrutiny of compatibility or alterations in the social setting of research subjects. Methods. Subjects include adult, Indian-origin rhesus macaques assigned to research protocols involving SIV infection and anticipated development of SIV disease (i.e. not subject to vaccines, other prophylactic measures, or experimental treatments). The total number of subjects studied will be 32 of each sex. Using behavioral, physiological, immunological and clinical data, changes within individuals are assessed. In addition, effects of pair- versus single housing is being compared. Videotaped data collection begins prior to social introduction and SIV inoculation in order to document baseline profiles in single housing, and is repeated after introduction into pair housing and prior to infection. Within pairs, both members are inoculated on the same day. After inoculation, data are collected intensively for the first month. After the first month, a steady scheduling of less intensive data collection is followed until the endpoints approved by the Animal Care and Use Committee are reached. Results/Discussion. Twelve animals reached study endpoints and data coding has been initiated.